Amplifier



FIG. 1 is a front view of an amplifier;

FIG. 2 is a rear view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a perspective view thereof in a horizontal position (amplifier closed);

FIG. 6 is a perspective view thereof in a horizontal position (amplifier open); and,

FIG. 7 is a perspective view thereof in a vertical position (amplifier closed).

The partially broken lines represent the bounds of the claimed design while all other broken lines are included for the purpose of illustrating the unclaimed portions of the article; the broken lines form no part of the claimed design. 

The ornamental design for an amplifier, as shown and described. 